Background: With the aim to prevent sick building syndrome and worsening of allergic symptoms, primarily resulting from the indoor environment, the relationships among people's residential environment in recent years, their lifestyle habits, their awareness, and their symptoms were investigated using an online survey. Methods: In the survey, respondents experiencing symptoms specific to sick building syndrome, although they were not diagnosed with sick building syndrome, were categorized in the pre-sick building syndrome group. The relationships among individual characteristics, residential environment, and individual awareness were analyzed. Results: Results showed that the prevalence of pre-sick building syndrome was high among young (aged 20-29 years) population of both sexes. In addition, "condensation," "moisture," "musty odors" in the house, and the "use of deodorant and fragrance" were all significantly associated with pre-sick building syndrome. Conversely, there was no significant association with recently built "wooden" houses that are highly airtight and have thermal insulation. Conclusions: Efficient "ventilation" plans and "ventilation" improvement and air conditioning systems to prevent mold and condensation in rooms are necessary to maintain a good, indoor environment that is beneficial for health. Efforts should also be made to encourage individuals to regularly clean and effectively ventilate their homes.

Sick-building syndrome (SBS) is a range of symptoms such as eye irritation, sore throat, and headaches that occur when entering a newly constructed or refurbished building. Volatile organic compounds (VOCs) are suspected to be one of the major causes of SBS. However, although Ministry of Health, Labour, and Welfare of Japan set the guideline values for 13 VOCs, the incidences of SBS patients have not decreased. In addition, there have been reports that when people complained symptoms of SBS, most of them also claimed to smell an odour. Furthermore, the occurrence of SBS symptoms depends largely on the person’s sensitivity. In this study, the correlation between the sum of VOCs(C2-C16) including aldehydes (ΣVOCs) and SBS symptoms were examined by statistics. The odour was quantified using the odour threshold ratio (OTR) and the correlation between the total odour threshold ratio (TOTR: sum of the OTR) and SBS symptoms was investigated. These correlations were examined separately for sensitive and insensitive groups. TOTR and the concentration level of ΣVOCs were correlated with SBS symptoms among sensitive people. The findings indicate that TOTR, in addition to ΣVOCs, could be used as a new risk indicator for human health regarding indoor air quality.

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Nowadays, people spend most of their time indoors; thus, the indoor environment greatly affects human health because of exposure to chemicals indoors. Thus, in collaboration with Japanese house builders, a list of building materials having low volatile organic compound concentrations was compiled herein. The air-quality samples from seven newly built houses (seven bedrooms and seven living rooms) were collected and tested for 64 volatile organic compounds and two aldehydes. Air samples were obtained from the house with no furniture or household goods and were sampled 1 week after construction and repeated after a month. Furthermore, the test results with a 2009 survey of indoor air quality in newly constructed houses were compared. One week after construction, the xylene, styrene, toluene, formaldehyde, and ethylbenzene concentrations were less than half the standard guideline values set in Japan. The main substances detected in the samples were 2-butanone, acetone, ethanol, ethyl acetate, butyl acetate, and undecane. The statistical significance of the changes in substance concentrations over time was examined via Wilcoxon signed-rank test. One month after construction, the concentrations of all chemical substances had undergone a statistically significant reduction, except butyl acetate. The median of total volatile organic compounds in living rooms was 291 µg/m 3 , and the maximum was 354 µg/m 3 ; both were under Japan's provisional total volatile organic compound target of 400 µg/m 3 . These values were significantly lower than those recorded by other researchers. This study concludes that using experimentally identified low volatile organic compound materials effectively improves the indoor air quality.

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Inadequate maternal iodine intake affects thyroid function and may impair fetal brain development. This study investigated the association between maternal iodine intake during pregnancy and neurodevelopmental delay in offspring at 1 and 3 years of age using a nationwide birth cohort: the Japan Environment and Children’s Study. We assessed dietary iodine intake during pregnancy using a food frequency questionnaire and child neurodevelopment using the Japanese translation of the Ages and Stages Questionnaire, Third Edition. The risk of delay (score below the cut-off value) for fine motor domain at 1 year of age was increased in the lowest quintile iodine intake group compared with the fourth quintile iodine intake group. The risk of delay for problem-solving at 1 year of age was increased in the lowest and second quintile iodine intake group and decreased in the highest quintile iodine intake group. The risk of delay for communication, fine motor, problem-solving, and personal–social domains at 3 years of age was increased in the lowest and second quintile iodine intake group compared with the fourth quintile iodine intake group, while the risk of delay for fine motor and problem-solving domains was decreased in the highest quintile iodine intake group. Low iodine intake levels in pregnancy may affect child neurodevelopment.

Globally, sick building syndrome remains a considerable social issue. It is primarily caused by the emission of volatile organic compounds (VOCs) from construction materials. Among these, paints and sealers are used over wide swaths of are a and their use causes chemical substances to be released in a room. To prevent sick building syndrome, it is necessary to clarify the cause of air quality changes due to the different types of paints and sealers available. Recently, low-VOC paints (containing 0.3-1.0% VOCs) have been used widely; however, the effects of reducing VOC levels have not yet been fully quantified. This study aims to clarify the chemical compositions by conducting an emission rate test of these low-VOC paints and sealers. We prepared six specimens and used them for chamber testing. Three types of paint with and without a sealer were tested. The minimum and maximum total volatile organic compound (TVOC) concentration was 96 and 4750 μgm −2 h −1 , respectively. Differences in the VOC content of the paints and sealers could be confirmed. The main TVOC was Texanol ™ and glycerol ethers. The results demonstrate that using paints containing less than 0.3% VOCs can decrease the VOC emission rate considerably compared to paints classified as less than 1% VOCs. Moreover, because different kinds of sealers affected the results, it is possible to decrease VOC emission rate using a variety of sealers.